The present invention relates to a device serving to support and drive the unit by which labels are gummed and transferred in a labeling machine.
Conventional labeling machines, and in particular high speed machines with an output capacity of 40 to 50 thousand pcs/h, generally comprise a rotary platform of which the periphery affords a plurality of plates to receive containers for labeling.
In the course of its rotation, the platform passes through one or more labeling stations comprising a label dispensing magazine, a gumming roller and a transfer drum disposed about a center station with revolving segments or paddles.
The segments are smeared with glue by the gumming roller in such a way as to pick up the labels from the magazine; each label clings to the respective segment by way of its reverse side and is conveyed thus to the transfer drum, taken up by grippers, and applied to one of a succession of containers conveyed through the machine.
The gums are utilized cold, and generally will be water soluble, polyvinyl or casein based adhesives. In labeling machines of the type in question, the gumming roller and the center station supporting the segments will stand generally on a base or bed housing the prime mover of the machine and the transmission components, which are oil-immersed. In order to prevent the risk of gum leaking down toward the delicate mechanisms and trains of gears located internally of the base, use is made of rubber couplings, O-rings, labyrinth seals, etc., that is, parts designed to ensure a fluid-tight barrier.
The main drawback encountered in such machines is that the gum, albeit initially fluid, tends to dry out during standstill periods and solidify into lumps that can ruin a seal fashioned in rubber. Metal labyrinth seals are also affected, becoming partly obstructed by a sediment of adhesive matter and tending consequently to generate a pumping effect when in rotation; this, for example, favors an undesirable suction of water and/or gum during cleaning operations.
Such problems are overcome currently by dismantling the affected parts and cleaning them separately, though this is a lengthy procedure when compared with the more simple expedient of spray-washing the machine prior to shutting off the drive.
Despite such precautionary measures, moreover, bearings still need to be replaced periodically, and indeed somewhat frequently.
In most cases, the labeling unit is mounted to a slide with crossed slots (of dovetail profile) on which the components can be traversed in a radial direction to give positioning along two mutually perpendicular axes and thus permit of adjusting the timing and pressure with which the label is applied during operation of the machine.
Thus, the slide constitutes a further part of the machine exposed to the spilled adhesive.
The object of the invention is to overcome the drawbacks mentioned, and in particular to embody a device for supporting and driving the gumming roller and the center station with its associated segments, such as will both disallow any leakage of water and/or gum into the internal drive mechanisms of the machine and enable an easy recovery of water or washing liquid at one and the same time.
A further object of the invention is to permit of washing down the labeling machine either manually or automatically without the need to dismantle any of its component parts.
Another object of the invention is to afford ease of access to transmission components of the device and thus facilitate inspection and servicing.